The study has two objectives: (1) Investigate the relative influence of genetic and experiential factors in the development of drinking patterns, psychopathology, and personality traits, by comparing adolescents of alcoholic parentage with controls of non-alcoholic parentage in a 15-year follow-up of an extensively studied obstetrical cohort. (2) Use this information as a data base for subsequent follow-up of the cohort into adulthood to identify high-risk factors antedating the onset of drinking problems and other psychopathology. The sample consists of 300 male individuals (age 15-17) who were in a group of 9,182 children studied perinatally and during the first year of life by physicians at the University of Copenhagen, Denmark. Two-hundred subjects had a parent treated for alcoholism. The other 100 subjects are controls matched for age, sex, and socioeconomic class of the parent. Phase 1 (this grant) involves studying the children just as they are entering the age of risk for the development of drinking problems. The examination includes interviews with the parents; a psychiatric and psychosocial interview of the children; neuropsychological and psychological tests; a neurological examination; psychophysiological and neurophysiological recordings; and biochemical studies. Phase 2 of the study involves periodic reexamination of the subjects over a period of 10-15 years to identify factors that predict drinking problems and other psychopathology in later life.